JP2002047927A - Catalytic converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalytic converter having improved thermal insulating characteristics. SOLUTION: A catalytic converter 110 includes a converter shell 112, at least one tapered end part parts 114 provided with a flange 116 and a thermal shield 122. The thermal shield 122 extends in a shaft direction from the converter shell 112 and surrounds the end part parts 114 and the flange 116 on at least one part of the surrounding part of the converter 110.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a catalytic converter for an internal combustion engine exhaust system and, more particularly, to a highly thermally insulated catalytic converter.

[0002]

BACKGROUND OF THE INVENTION In the field of vehicle engine exhaust gas catalytic converters for controlling exhaust gas, it is known to provide a housing with an insulated cylindrical shell. A tapered part assembly with a flange is welded to the shell to connect the converter to the exhaust gas pipe or component. The catalyst element is assembled to the cylindrical shell before placing and welding the end cone assembly on the shell. The shell may have a circular cross-section or may have any suitable non-circular shape.

[0003] During operation of the engine, the internal combustion engine exhaust gases pass through a converter, which heats the converter to a high temperature. To reduce the thermal radiation emitted from the catalytic converter shell, a metal or ceramic monolith is mounted in the catalytic shell by a heat insulating blanket. This blanket can be composed of a mat made of heat resistant ceramic fibers.

[0004] However, the use of double cones for the end pieces and the use of insulating fibers between the double cones has limited their usefulness. In fact, the outer wall is insulated from the inner wall by the air gap of the fiber mat. Nevertheless, the outer wall is heated by radiation and conduction of the flange, at which point the two walls of the end piece are assembled together. Furthermore,
The flange itself is also a significant heat source.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a catalytic converter having improved thermal insulation.

[0006]

SUMMARY OF THE INVENTION To solve the above problems, the present invention provides a catalytic converter that includes a converter shell and at least one tapered end piece having a flange and a heat shield. This heat shield
An axial extension from the converter shell and surrounding the end piece and the flange on at least a portion of the perimeter of the converter.

The heat shield of the catalytic converter forms the outer shell of the tapered end piece and the mounting flange. The outer shell extends over at least a portion of the periphery of the converter. Thus, the heat shield shields the heat radiation emitted from the tapered end piece and the enclosed portion of the flange, thereby protecting the vehicle floor, i.e., any engine elements located beyond the heat shield. I do. The heat shield preferably extends beyond the outer flange so that heat radiation from the flange itself can be effectively shielded. It will be appreciated that heat transfer from the flange to the heat shield is not possible because the heat shield is not assembled to the flange.

It should be noted that the heat shield can surround the tapered end piece and flange throughout the radial periphery of the converter. In this case,
The heat shield forms a kind of pipe with a section substantially equal to the section of the converter shell. In an alternative embodiment,
The heat shield surrounds only the tapered end and a portion of the periphery of the flange. In this case, the heat shield
It forms only a section of pipe and is located on the perimeter of the converter in certain areas and is oriented towards important engine or vehicle parts.

In any case, it will be appreciated that the heat shield represents a very effective thermal insulation, combining effectiveness with low manufacturing costs. In fact, the heat shield provides better thermal insulation, especially when surrounding the entire periphery of the end piece, than a double cone assembly whose manufacturing process requires expensive tooling. Due to better thermal insulation when compared to prior art converters, the end parts of the catalytic converter of the present invention do not need to be a double cone assembly, thus reducing the cost of manufacturing the converter Is added.

[0010] The heat shield may be a separate part welded to the converter shell. However, in a more preferred embodiment, the heat shield is an integral part of the converter shell. In other words, the converter shell is designed to extend beyond the catalytic element or thermal insulation blanket, at least on a part of its periphery,
The inner end is assembled, for example by welding, to the inner surface of the protruding end of the shell or heat shield. It will be appreciated that this embodiment represents a very simple concept for providing a heat shield on a catalytic converter.

In a very simple embodiment, the tapered end pieces are simple cones each welded on the inside surface of the heat shield of the converter shell. To provide a stop for the thermal insulation blanket between the catalytic element and the converter shell, the tapered end piece preferably includes a bread on its inner end, wherein the bread is radial. It has an outer perimeter that extends outwardly and is substantially equal in shape and size to the inner surface of the heat shield. In this embodiment,
The axial outside of the peripheral breadt can act as a stop for the insulating blanket. Furthermore,
Due to the bread, the opening angle of the end cone itself is
In this embodiment, it is reduced. This improves the ease of connection between the tapered end part and the inner surface of the converter shell, thus simplifying the assembly of the two parts, for example by welding.

If improved thermal insulation is required due to the mounting of the catalytic converter in the critical position, the tapered end piece may be a double-walled cone assembly with an outer cone and an inner cone. The inner cone may be coaxially arranged within the outer cone. Furthermore, it is preferred that the insulating material is located within the gap between the inner and outer cones of the tapered end piece. This embodiment increases manufacturing costs due to the double-cone assembly, but nevertheless provides unmatched thermal insulation.

In a simpler embodiment with improved insulation properties, the heat shield is a double wall assembly having an outer wall and an inner wall, wherein the inner wall is coaxially arranged within the outer wall, The outer wall and the inner wall are mounted together on an outer end of the heat shield. In this embodiment, the outer wall of the heat shield may be an integral part of the converter shell, and the inner wall may be mounted on the outer end of the outer wall, for example, by welding or indentation. It should be noted that this embodiment is easy to assemble because the end cone assembly can be assembled to the inner wall of the heat shield before insertion into the converter shell. This means that the welding of the end pieces and the inner wall takes place outside the converter shell, so that the welds are easily accessible. After the two parts have been mounted together, they can be introduced axially into the protruding end of the converter shell, and the inner wall is subsequently assembled to the outer end of the outer wall. In this way, again, it is preferred that the insulating material be located in the gap between the inner and outer walls of the heat shield, to further improve the insulation properties of the heat shield, where the weld is easily accessible. . This insulating material can be, for example, part of a thermal insulating blanket located between the catalytic element and the converter shell.

The present invention will become more apparent from the following description of embodiments with reference to the accompanying drawings. In addition, the present invention
It is not limited to the following embodiment.

[0015]

FIG. 1 shows one end of a conventional catalytic converter. It comprises a converter shell 12,
To this shell, a tapered end piece 14 with a flange 16 is welded to connect the converter to an associated exhaust gas pipe or component. The catalyst element 18 is assembled to the converter shell 12 before placing and welding the end cone assembly 14 on the shell. To reduce the heat radiation emitted from the shell 12 of the catalytic converter 10, a catalytic element 18 is mounted in the catalytic shell by a thermal insulating blanket 20. This blanket can be comprised of a mat made of heat resistant ceramic fibers. Further, the tapered end piece 14 includes an outer cone 22 and an inner cone 24.
A double-walled conical assembly with The inner cone is coaxially arranged inside the outer cone 22 and the space between the two cones is filled with insulating fibers 26.

[0016] Although the double cone assembly substantially reduces heat radiation for a single conical end piece, the assembly nonetheless incorporates an inner cone and an outer cone together. However, overheating of the outer conical portion due to heat conduction from the flange 16 cannot be prevented. Furthermore, the flange itself is a significant heat source.

FIG. 2 shows a first embodiment of the improved catalytic converter 110 according to the present invention. As in the prior art converter, converter 100 includes a converter shell 12 in which a tapered end piece 114 having a flange 116 connects the converter to an associated exhaust gas pipe or component. To be welded. The shell 112 has a circular cross-section or may have any suitable non-circular shape. The catalyst element 118 is mounted on the end cone assembly 11 on the shell.
4 is assembled to the converter shell 112 before installation and welding. To reduce the heat radiation emitted from the shell 112 of the catalytic converter 110, the catalytic element 1
18 is mounted in the catalyst shell by a heat insulating blanket 120. This blanket can be composed of a mat made of heat resistant ceramic fibers.

To eliminate the deficiencies of prior art converters, converter 110 of the present invention includes a heat shield 122. The heat shield 122 is connected to the converter shell 11.
2 extends axially from end piece 114 and flange 1
16 on at least a portion of their periphery.
The heat shield preferably extends beyond the flange 116 such that the flange 116 is totally shielded.

The heat shield 122 is connected to the converter shell 1
It is preferably an integral part of 12. The tapered end piece has a projecting end or heat shield 122 of the converter shell 112 until its inner end 124 abuts the catalytic element 116 or heat insulating blanket 120.
Is inserted into. Subsequently, the end piece 114 is assembled to the protruding end of the converter shell, ie the inner surface of the heat shield, for example by welding 126. It will be appreciated that this embodiment represents a very simple concept for providing a heat shield on a catalytic converter.

In the embodiment shown in FIG. 2, the tapered end piece 114 includes a single cone 130 welded on the inner surface 128 of the heat shield 122. This conical part 13
The 0 preferably has a bread 132 on its inner end. The bread extends radially outward and has an outer perimeter that is substantially equal in shape and size to a section of the inner surface of the heat shield 122. In this embodiment, the axially outer surface 124 of the peripheral bread 132 can act as a stop for the insulating blanket 120.

A second embodiment of the improved catalytic converter is shown in FIG. In this embodiment, the tapered end piece 114 includes an outer cone 134 and an inner cone 1.
36 includes a double-walled conical assembly. The inner cone 136 is coaxially arranged within the outer cone 134.
Further, the inner conical portion 13 of the tapered end piece 114
6 and the insulating material 1
38 are preferably arranged. This embodiment increases manufacturing costs due to the double-cone assembly, but nevertheless provides unmatched thermal insulation.

Another embodiment of the present invention with improved properties is shown in FIG. In this variation, the heat shield 122 is a double wall assembly with an outer wall 140 and an inner wall 142, wherein the inner wall 142 is
It is arranged coaxially within 0. Outer wall 140 and inner wall 14
2 are mounted together on the outer end 144 of the heat shield 122, which can be an integral part of the converter shell 112, and the inner wall 142 is welded or recessed on the outer end of the outer wall 140, for example. It is attached as such.

The end cone assembly 114 is connected to the inner wall 14.
2 on the inner end 148 (14
6). The insulating material 150 is applied to the inner wall 1 of the heat shield 122.
It is located in the gap between 42 and outer wall 140.
The insulating material 150 may be, for example, a portion of a thermal insulating blanket 120 disposed between the catalytic element 118 and the converter shell 112.

[Brief description of the drawings]

FIG. 1 shows one end of a prior art catalytic converter.

FIG. 2 shows a portion of a first embodiment of the improved converter.

FIG. 3 shows a part of a second embodiment of the improved converter.

FIG. 4 shows a portion of a third embodiment of the improved converter.

[Explanation of symbols]

 110 catalytic converter 112 converter shell 114 tapered end piece 116 flange 122 heat shield 128 inner surface 132 bread 134 outer cone 136 inner cone 138 insulating material 140 outer wall 142 inner wall 144 outer end

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Steve Maize Grand Duchy of Luxembourg 5415 Kanaf, Lou Yère 10 F-term (Reference) 3G004 AA01 BA05 BA06 DA14 DA15 EA05 FA04 FA07 GA06 3G091 AB01 BA03 BA39 FA02 FB02 FB03 FC07 FC08 GA06 GB01X GB01Z GB10X GB16Z 3H036 AA09 AB01

Claims (9)

[Claims] 1. A catalytic converter (110) comprising a converter shell (112) and at least one tapered end piece (114) with a flange (116), further comprising a heat shield (122). Including the heat shield (12
A catalytic converter (110), characterized in that 2) surrounds the end piece (114) and the flange (116) on at least a part of the periphery of the converter (110). 2. The catalytic converter according to claim 1, wherein the heat shield is an integral part of the converter shell (112). 3. The tapered end piece (114) comprises:
The catalytic converter according to claim 1 or 2, wherein the catalytic converter is assembled to an inner surface (128) of the heat shield (122). 4. The tapered end piece (114)
An inner end facing the converter shell (112);
An outer end terminating in the flange (116), the tapered end piece (114) including a bread (132) on its inner end, the bread (13).
2) extends radially outward and includes the heat shield (1).
The catalytic converter according to claim 3, characterized in that it has an outer perimeter that is substantially equal in shape and size to the section of the inner surface (128) of (22). 5. The tapered end piece (114)
A double-walled cone assembly comprising an outer cone (134) and an inner cone (136), wherein the inner cone (13
6) is coaxially arranged within the outer cone (134);
The catalytic converter according to claim 1. 6. The inner cone (136) and the outer cone (134) of the tapered end piece (114).
The catalytic converter according to claim 5, comprising an insulating material (138) disposed inside the gap between the two. 7. The heat shield (122) is a double wall assembly having an outer wall (140) and an inner wall (142), wherein the inner wall (142) is connected to the outer wall (140).
The outer wall (140) and the inner wall (142) are coaxially arranged within, and the outer wall (140) and the inner wall (142) are mounted together on an outer end (144) of the heat shield (122).
The catalytic converter according to any one of the above. 8. The outer wall (140) of the heat shield (122) is an integral part of the converter shell (112), and the tapered end piece (114) is connected to the inner wall (142). The catalytic converter according to claim 7, mounted on the inner end (148). 9. The heat shield (122) comprising an insulating material (150) disposed within a gap between the inner wall (142) and the outer wall (140). Catalytic converter.